This invention relates to a novel tape cassette, and more particularly to a novel tape cassette of a small size which includes a lid member for covering over, when the tape cassette is not used, a recording medium tape to protect the recording medium tape and a locking member for locking the lid member at a closed position at which the lid member protects the recording medium tape.
A tape cassette normally includes, in order to protect a portion of a recording medium tape such as a magnetic tape positioned along a front face of a tape extraction recessed portion formed on a front face of a cassette case formed from upper and lower halves, a lid member for removably covering over the portion of the magnetic tape.
An exemplary one of tape cassettes of the type described above is shown in FIGS. 11 and 12.
Referring to FIGS. 11 and 12, the tape cassette shown is generally denoted at a and is constituted from an upper half c and a lower half d coupled in a vertically aligned relationship to each other.
A recessed portion e called mouth portion is formed at a substantially center of a front portion of the cassette case b such that it is opened forwardly and upwardly and downwardly.
A magnetic tape f is wound on a pair of tape reels not shown and accommodated in the cassette case b. A portion of the magnetic tape f is led out from the cassette case b to the outside and is positioned, when the tape cassette a is not used, along a front face of the mouth portion e.
A lid member g is provided to cover over, when the tape cassette a is not used, the portion of the magnetic tape f led out from within the cassette case b to protect the magnetic tape f. The lid member g is formed from a front lid h and a back lid i.
The front lid h has a front portion j for covering over the front face side of the magnetic tape f and a pair of side portions k (only one is shown in FIGS. 12 and 13) extending rearwardly from the opposite side edges of the front portion j. A pivot shaft 1 is formed on each of the side portions k of the front lid h.
A spring anchoring projection m is formed on one of the side portions k of the front lid h.
The front lid h is supported for pivotal portion on the cassette case b with the pivot shafts 1 thereof fitted in a pair of support holes formed at front end portions of a pair of side walls of the cassette case b.
A torsion spring n is fitted at a coiled portion o thereof around one of the pivot shafts 1 and has an arm p resiliently contacted from above with the spring anchoring projection m. The other arm q of the torsion spring n is resiliently contacted with a locking member which will be hereinafter described.
The back lid i has a main portion r in the form of a plate and a top plate portion s formed integrally at the top end of the main portion r. The back lid i is supported, at portions of the opposite side portions of the main portion 4 a little lower than the middle position in the vertical direction, for pivotal motion on the inner face side of the front portion j of the front lid h.
A pair of projections t (only one is shown in FIGS. 11 and 12) extend rearwardly from lower end portions of the opposite side edges of the main portion r of the back lid i, and a pair of guide pins u (only one is shown in FIGS. 11 and 12) are formed on outer side faces of rear end portions of the projections t. The guide pins u are held in sliding engagement with a pair of guideways not shown formed on the opposing inner side faces of the mouth portion e.
A locking member v is provided for locking the lid member g at a closed position when the tape cassette a is not used. The locking member v has a substantially vertically elongated profile and is supported at an upper end portion thereof for pivotal motion on one of the side walls of the cassette case b.
The locking member v has a spring anchoring portion w formed at an upper end thereof such that it projects rearwardly a little, and the arm q of the torsion spring n resiliently contacts from above with the spring anchoring portion w. Consequently, the locking member v is normally acted upon by a resilient pivoting force in the clockwise direction in FIGS. 11 and 12, that is, in a direction in which a lower end portion of the locking member v moves forwardly so that it is engaged at an engaging portion thereof with an engaging portion formed on one of the side portions k of the front lid h under the resilient pivoting force to lock the front lid h at its closed position.
When the tape cassette a is loaded into a recording and reproduction apparatus, an unlocking member provided on the recording and reproduction apparatus pushes a lower end portion of the locking member v relatively rearwardly to cancel the engagement between the engaging portion of the locking member v and the engaging portion of the front lid h to allow movement of the lid member g toward its open position.
Then, when the tape cassette a moves down to a predetermined loaded position, a lid opener not shown provided on the recording and reproduction apparatus is contacted with the lower edge of and pushes one of the side walls k of the front lid h relatively upwardly so that the front lid h is pivoted upwardly against the resilient pivoting force of the torsion spring n. Thereupon, also the back lid i is pivoted with its posture controlled by movements of the pivotal support points thereof supported on the front lid h and guidance of the guide pins u by the guideways until it comes to its open position shown in FIG. 12.
Consequently, the portion of the magnetic tape f positioned along the front face of the mouth portion e is opened or exposed outside.
A pair of substantially semi-circular recesses y (only one is shown in FIGS. 11 and 12) are formed at locations adjacent the front ends of the lower edges of the side walls of the upper half c and serve as support holes for supporting the pivot shafts 1 of the front lid h.
A stopper portion z is formed at a lower edge portion of an outer side face of one of the side walls of the upper half c at a location a little rearwardly of the position at which the recess y is formed.
Upon production of the tape cassette 1, the lid member g is temporarily fastened to the upper half c before the upper half c and the lower half d are coupled to each other.
In particular, the pivot shafts 1 of the front lid h of the lid member g in which the back lid i is assembled to the front lid h are engaged in the recesses y of the upper half c while the coiled portion o of the torsion spring n is fitted around one of the pivot shafts 1 and the arm p of the torsion spring n is resiliently contacted with the spring anchoring projection m, and the other arm q of the torsion spring n is resiliently contacted from above with the stopper portion z to exert an upwardly moving force to the pivot shafts 1 until the pivot shafts 1 are stopped by top portions of the recesses y to temporarily fasten the lid member g to the upper half c.
Meanwhile, the locking member v is temporarily fastened to the lower half d.
Then, when the upper half c and the lower half d are coupled to each other, since the spring anchoring portion w of the locking member is positioned at a higher position than the stopper portion z when the cassette case b is in an assembled condition, the arm q of the torsion spring n resiliently contacts from above with the spring anchoring portion w of the locking member v to exert a pivoting force to pivot the locking member v toward its locking position, that is, in the clockwise direction in FIGS. 11 and 12. In this condition, however, since the locking member v will be pivoted excessively in the clockwise direction until it abuts with the front lid h, the locking member v cannot be assembled.
Further, when the tape cassette a is loaded into a recording and reproduction apparatus, the lower end portion of the locking member v is pushed rearwardly by the unlocking member x to unlock the lid member g from the locking member v as described above. In this instance, there is no problem if the unlocking member x keeps the locking member v at its unlocking position even after such unlocking, but if not, the locking member v will be pivoted excessively in the clockwise direction. Consequently, when the lid member g returns to its closed position, it cannot be locked by the locking member v.
Therefore, an abutting portion .alpha. is formed at a front edge portion of the locking member v such that it abuts from below with the stopper portion z of the upper half c to prevent the upper half c from pivoting in the clockwise direction any more.
In the conventional tape cassette as described above, the stopper portion z must be provided between the fulcrum of pivotal motion of the lid member g and the fulcrum of pivotal motion of the locking member v, and the position at which the stopper portion z is provided is limited to a position at which the arm q of the torsion spring n can be temporarily fastened to and the abutting portion .alpha. of the locking member v can be contacted with the stopper portion z.
Accordingly, when it is intended to promote minimization, the space for formation of the stopper portion z makes a dead space and provides a disadvantage to minimization.